Britain's Harriet Dart overcame Marie Bouzkova in a topsy-turvy match to set up a second-round encounter with top seed Elena Rybakina at Eastbourne.
Roared on by a partisan home crowd, Dart fought back from a double break down in both the first and second set before wrapping up a 7-5 6-7 (7-9) 6-4 victory in nearly three and a half hours.
It is Dart's best win of the year by ranking, with the 27-year-old wildcard ranked 68 places below Czech Bouzkova.
She will face former Wimbledon champion and world number four Rybakina, who received a bye in the first round, on Wednesday.